The present invention relates to a method and apparatus for profiling a log, particularly for cutting a reentrant corner in the log that extends along the log.
To process logs into standard lumber, the logs are first slabbed on one to four sides. To avoid waste and, because the cross-section of the log is generally round, this processing intentionally leaves four rounded corners. Referring first to FIGS. 1A and 1B depicting, respectively, the cross-section of the log before and after being slabbed on four sides and then turning to FIG. 1C, the rounded corners are removed by cutting into the log along its longitudinal axis corresponding reentrant corners xe2x80x9cC.xe2x80x9d This squares portions of the log, indicated in the Figure as xe2x80x9cAxe2x80x9d, that are located between the contours of adjacent corners so that the portions are configured to be cut into pieces of standard lumber. Forming the corners C is typically referred to as xe2x80x9cprofilingxe2x80x9d and an apparatus adapted for this purpose is typically referred to as a xe2x80x9cprofiler.xe2x80x9d
An example of a prior art profiler is shown in FIG. 2. First and second knives 2 and 4, which are identical, are disposed on the circumference of a rotating disc 6. A slabbed log 8 having an elongate axis xe2x80x9cLxe2x80x9d is fed toward the disc along a circumferential direction xe2x80x9cd.xe2x80x9d The cutting edge of the first knife is oriented parallel to the axis of rotation of the disc and the cutting edge of the second knife is oriented in a plane of rotation of the disc. Referring back to FIG. 1C, the first knife cuts a first leg xe2x80x9c11xe2x80x9d of a particular reentrant corner C and the second knife cuts a perpendicular, second leg xe2x80x9c12xe2x80x9d of the reentrant corner, wherein the legs 11 and 12 meet at a region of intersection xe2x80x9cc1xe2x80x9d of the corner C. It should be understood that the legs xe2x80x9c11xe2x80x9d and xe2x80x9c12xe2x80x9d are the visible portions of planar surfaces extending along the longitudinal axis of the log.
Another example of a prior art profiler replaces the second knife with a sequence of cutting teeth disposed around the periphery of the disc, such as the teeth of a saw blade.
In both of these profilers, the first and second knives are disposed so that the first knife meets the log at a different time than does the second knife. Because there is relative movement between the disc and the log, this time difference provides an opportunity for the two cuts to fail to intersect precisely at the same corner region c1 and thereby fail to form a clean or smooth corner C. In particular, there often results, running longitudinally along the corner C, xe2x80x9cfeathersxe2x80x9d or slivers of wood partially but not completely removed from the log, or other unevenness in the surface texture of the corner. This result is often aggravated further as wear occurs in the apparatus.
Accordingly, there is a need for a method and apparatus for profiling a log that provides for the formation of smoother surfaces in corners cut thereby and for maintaining this capability despite wear in the apparatus.
A method and apparatus for profiling a log according to the present invention solves the aforementioned problems and meets the aforementioned needs by providing in a profiler having first and second knives disposed on a rotating disc, wherein the first and second knives have respective cutting edges defining an angle therebetween that is typically but not necessarily 90 degrees, a mounting member that is adapted to mountably receive both the first and second knives so that each blade has a point on its cutting edge that is proximate a point that is on the cutting edge of the other knife. Preferably, the points of the cutting edges that are proximate are the ends of the cutting edges and, preferably, the proximity is such that the points abut one another.
Preferably, an abutting relationship of the tips of the knives is maintained against the forces typically encountered by the knives during use. The knives preferably include keyways that mate with corresponding keys in a mounting member for holding the knives. The keyways and keys substantially prevent the knives from moving in response to the forces.
In another aspect of the invention, the cutting edge of at least one of the knives is angled to avoid cutting the log parallel to the grain, to further improve the surface finish in profiling the log.
Therefore, it is a principal object of the present invention to provide a novel and improved method and apparatus for profiling a log or other elongate article.
It is another object of the present invention to provide such a method and apparatus that provides for the formation of smoother surfaces in corners cut thereby.
It is still another object of the present invention to provide such a method and apparatus that provides for maintaining the aforementioned capability despite wear in the apparatus.